Henrik Stenson will take a convincing lead in to the weekend at the Tour Championship, where Jordan Spieth surged up the leaderboard.
Stenson's previous appearance at East Lake saw him lead from start to finish to win the FedExCup title and US $10m bonus to go with the tournament first prize of US $1.4m.
And the Swede remains on course to repeat the feat after a two-under 68 gave him a three-shot lead over nearest challenger Spieth, who pulled himself back into contention with a round-of-the-day 66.
Any time you can maintain or extend your lead is always going to be a good day," Stenson said. "I did not feel like I played my best golf today but made some nice putts for birdie and kept it together pretty nicely."
Resuming two shots clear of Paul Casey after an opening round of 63, Stenson was able to double his advantage by the turn in difficult scoring conditions at a rain-soaked Atlanta.
Casey briefly moved within a stroke of the lead with a seven-foot gain at the first, only for the Swede to birdie two of his opening four holes.
After Stenson and Casey bogeyed the fifth, the Englishman lost further ground by double-bogeying the next after hooking his tee shot in to a water hazard.
That temporarily left Zach Johnson in second spot after the Open champion posted back-to-back gains at the seventh and eighth, only to run up a double-bogey seven and bogey the following two holes.
Gains at the ninth and 12th lifted Casey into joint-second alongside Spieth, who completed his bogey-free round with a 20-footer at the last.
A birdie on the 12th kept Stenson comfortably in front, although the Swede missed the chance to restore his four-shot cushion with a two-putt par from nine feet at the last.
Casey lies four shots off the pace after a blemish at the last, with Johnson a further stroke adrift despite closing his round with back-to-back gains.
